There will be as many ways of going about it as there are people … My first piece of advice is always play a lot of games of the type you're going to write and make a note of things you love about them and things you hate about them - then you know what to include / exclude in your game. Read the reviews on the type of game you're going to make - people are very vocal about things they like / hate in games - for example if you're writing for the casual market - DO NOT shake the screen. (Not the reviews on itch. io - go read them on sites where the reviewers are anonymous or websites that are trying to make a living out of reviews.)
Consider these questions first because you have to plan for them:
- What screen size are you aiming for – Windows 10 would be 1920x1080 – I have no Idea what Mac screen sizes are. Are you going to allow user to switch between full screen and window mode? Do you foresee porting it to mobile in the future – in which case you’d make it smaller or you’ll have to remake it.
- Will there be music and sounds and the option to switch them off if the player doesn’t want them on?
- Are you going to have different skill levels? Casual vs Expert?
- Will there be hints? How often, do they recharge?
- What’s going to make the game fun to play? What’s going to keep the person playing it interested?
- What’s your hook or angle? What’s going to attract people to your game?
- Will there be a story? When is it going to appear? Can they skip it?
- Will there be an option to restart a level / scene?
- Is the game timed / not timed / will the player have an option to choose?
- How long should each level last? This is the difference between giving a player 10 items to find or 30 etc.
- If they struggle with a particular puzzle what will they do? Can they skip it? Will they be stuck there forever? Will the hints show them? If they skip it, can they still continue the game?
- Will there be awards or achievements?
My first step after that is to create mock layouts in a graphics programme so that I can get the size ratio right. Once I have that I can create my graphics and export them in the right sizes and set them up in the game development software. It's up to you what your game looks like - but take the time to play - try different things - see what looks good to you.
I plan my levels in Excel and the coding blocks or sections I’ll need – in this case you’d have to plan every scene / puzzle etc. I also create a sheet with TO DO NEXT – and I make notes there as I go along, as I discover things I want extra, to change, to check etc. I'll also list all the variables I'll need etc.
If I have a story in my game, I write that in Word (or if I’m lucky someone else writes that in Word), plan the story screens, when they will appear – if they restart the level will you suppress the story or must they read it again? Is it something someone will want to read? Can they skip it?
I plan my game in blocks so that I know – Monday I’ll do this, Tuesday I’ll do that etc. It helps keep me focused so that when I open the game I don’t have to wonder – what should I do today…I don't beat myself up about it though, if Monday's work takes two days instead of 1 then I just adjust the schedule. It's just so that I know what needs to be done next.
If I’m not sure the game will be “fun” I’ll create a level with make-shift graphics and test it first. This allows you to pick up problems, for example if it’s going to be too easy, too difficult, too boring etc. That’s a good time to think of ideas to improve it or rethink the concept if necessary.
Once I have a “template” level of what will work I concentrate on getting the final graphics / sounds etc. ready and then create the levels using that template level to complete the game.
Other factors:
Have a look at the forums of the software you’re going to use. If you get stuck with coding parts of it – that’s going to be where you’ll need to go for help, so is there a community there that can help you? Do they have resources, tutorials? If there’s nothing there, then are you sure you want to use that software? If there’s support there, then go ahead.
Test things as you go along – got a background? Great - test it: Does it look as nice in your game? How much does it increase the size of your game? Should you split it - export it in 2 parts or 4 parts or is it okay if you have it as 1 solid graphic?
Don't rush it - take your time, if something doesn't work, change it. It's going to be okay if you release it next week or next month or next year...